Device for undercutting commutator insulation



J. F. CULLIN.

DEVICE FOR UNDERCUTTING COMMUTATOR INSULATION.

APPLICATION mp0 DEC. 29, 1919.

Patented 0017. 26, 1920.

JASPER r. CULLIN', or DETROIT, MICHIGAN, ASSIGNOR, BY

MESNE ASSIGNMENTS, TO

WILLIAM J. HARTWIG, OF DETROIT, MICHIGAN.

DEVICE FOR UNDERCIITTING COMMUTATOR INSULATION.

Specificationof Letters Patent.

Patented Oct. 26, 1920.

Application filed December 29, 1919. Serial No. 348,088.

To all whom it may concern.

Be it known that I JASPER F. CULLIN, a citizen of the United states, and residing at Detroit, in the county of Wayne and State of Michigan, have invented a new and Improved Device for Undercuttmg Commuta tor Insulation, of which the following 1s a specification. I

This invention consists in a pair of supports for the shafts of the armatures of electric motors and generators, and a reciprocating device embodying a saw moving longitudinally of thes shafts whereby the insulation between the segments of the commutators may be removed to a pre-determined depth.

This invention further consists in means for elevating the shaft support adjacent the commutator ends of the armatures in order that the commutators may be pressed against the reciprocating cutter.

It also consists in movably mountlng one i of the supports in order that the armature shafts may be swung out of alinement with the reciprocating cutter so that the reclprocating cutter may operate to remove the insulation between segments of the commutator when these are at an angle instead of being secured longitudinally of the shaft.

It also consists in the details of construction illustrated in the accompanying drawings and particularly pointed out in the claims.

In the drawings, Figure 1 is a plan of this improved insulation removing mechanism.

Fig. 2 is a side elevation thereof. Fig. 3 is a view on a larger scale of the cutter bar and a commutator positioned beneath it. Fig. 4 is a section on the line 44 of Fig. 1. Fig. 5 is an elevation of a foot lever for raising the commutators.

Similar reference characters refer to like parts throughout the several views.

Referring to the drawings, 1 is a base of any desired character on which is mounted a block 2 which constitutes a support for the anti-friction bearing sleeve 3 in which is mounted a shaft 4, any desired means being provided to keep this shaft from moving endwise, a pin 5 being shown in the drawlng extendin down across a groove 6 in the shaft. 11 one end of this shaft is a pulley 7 by means of which the shaft may be drlven,

I while the other end of the shaft is formed with a crank pin 8 on which is mounted a collar-9, preferably of hard steel, which is held in place by means of the washer 10' and the screw 11.

Slidable in this support 2 and held in position by the plate 13 and screws 14 is a cutter bar 15 which has secured to one end the bearlng plates 16 and 17 which are held spaced to properly engage the collar 9 by. means of the small blocks 18 and the screws 19. At the opposite end of this bar 15 in a rectangular depression is a short piece 20 of hack-saw material held in position by screws 21. The bar 15 is reciprocated horizontally by means of the crank pin 8.

Mounted on a pin 23 carried by the block 2 is a supporting lever 24 having a V-groove 25 at one end and which is connected at the other end by means of a link 26 to the foot lever 27 which is. pivoted on a small pedestal 28. Depression of the end 29 of this foot lever will elevate the notched end of the lever 24. It is apparent that this foot lever may be at any desired angle to the supporting lever 24 so as to accommodate the workman.

A plate 31 is movably secured to the base 1 by means of a bolt 32 and at-its opposite end it carries a pedestal 33 provided with a V-groove 34. The plate also has a slot 35 into which extends a pin 36 connected to the base 1. This plate 31 may be swung upon the screw 32 within the limits fixed by the slot 35 and the pin 36.

An armature 38 and its shaft 39 are shown in dotted lines resting in the V- grooves 25 and 34 in such position that the commutator 40 is 'ust below the saw 20. The insulations 42 etween the copper segments of these commutators are usually of mica which is much harder than the copper. Rid es of mica are therefore left on the "surface of the commutator after the machine has been in use only a comparatively short time because the copper between these ridges wears faster than the mica. After such wear has begun, arcing takes place and the copper soon becomes pitted. It is,

to the desired depth. The operation is extremely rapid, and the lever'29 is soon released and is moved upward by a spring 46 which permits the groove 25 to descend and carries the commutator out of engagement with the saw. The workman now turns the armature so as to bring anew insulation underneath the saw and again de re sseshis foot lever.

en the operator is skilled and all the' parts are in proper relation to each other, the undercutting of the insulation of a commutator need not, require more seconds than the number of segments in the commutator. The machine is so simple and has so few parts'to get out of order that the cost of upkeep is merely nominal. Inevery large shop hack-saw blades become broken or merely worn at a few points so that the raw material for these blades 20 is always on hand. a v

The details and proportions of this undercutting machine may all be modified by those skilled in the art without departing from the spirit of my lnvention as set forth in the following claims.

I claim 1. In an undercutting machine for the insulations of armature commutators, the combination of a reciprocating bar and a saw blade connected thereto, a pair of supports for the armature -shaft, and means to elevate one of the supports to bring the combination of a longitudinally reciprocating bar and means to actuate the bar, a

guide to support the bar, a cutter blade connected thereto, a pair of supports for the armature shaft, one of said supports being movable laterally, and means to move the other support vertically toward and from the cutter.

3. In an undercutting machine for insulations of armature commutators, the combination of a base and a block mounted thereon, a shaft mounted in the block and means to rotate the shaft, a cutter bar slidable in the block and a toothed cutter secured to one end thereof, a cam and slot connection between the opposite end of the bar and the shaft, a lever pivoted on the block to move in'a plane at right angles to the cutter bar and having a V-groove below the cutter, said lever being adapted to support one end 'of the armature shaft, means to swing the lever on its pivot, andlaterally movable means to support the opposite end of the armature shaft.

4. In an undercutting machine for the insulations of armature commutators, the

combination of a longitudinally reciprocating bar and means to actuate the bar, a guide to support the bar, a cutter blade connected thereto, a vertically movable support for the commutator end of the armature shaft, and a laterally movable supportf;t for the opposite end of the armature sha 1 JASPER F. QULLIN. 

